Why do I wake from a nap, with aching shoulders, I feel shaky all over, like I m shivering almost but not cold. I feel dizzy and weak. I know that I don t usually drop into delta level sleep, and these naps are always mid afternoon, and feel pretty deep, drool on the pillow deep. I had just eaten about 30 minutes or so, nothing heavy. I m a personal trainer, I eat very well. Thanks